Parallel_Op 0 (changes)
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ParallelDeviceDriver
» SWI Calls
» Parallel_Op
» Parallel_Op 0
Parallel_Op 0
(SWI &42EC1)
| Entry | |
|---|---|
| R0 | 0 (Reason code) |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Data register contents |
| R2 | Status register contents |
Status Register Contents
| Bit | Meaning | Port | Pin |
|---|---|---|---|
| 0 | Reserved | ||
| 1 | Reserved | ||
| 2 | Reserved | ||
| 3 | Error | 15 | |
| 4 | Select | 13 | |
| 5 | Paper error | 12 | |
| 6 | Acknowledge | 10 | |
| 7 | Not Busy | 11 |
Use
The purpose of this call is to read the data and status registers taken from the printer port.
Notes
The data register is eiter the current value on the port, or the last value written if output is enabled.
See also
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